/*
 * SPDX-FileCopyrightText: 2017 by Marco Martin <mart@kde.org>
 * SPDX-FileCopyrightText: 2021 Arjen Hiemstra <ahiemstra@heimr.nl>
 *
 * SPDX-License-Identifier: LGPL-2.0-or-later
 */

#include "basictheme_p.h"

#include <QGuiApplication>

#include "styleselector_p.h"

#include "loggingcategory.h"

namespace Kirigami {

class CompatibilityThemeDefinition : public BasicThemeDefinition
{
    Q_OBJECT
public:
    CompatibilityThemeDefinition(QObject *component, QObject *parent = nullptr)
        : BasicThemeDefinition(parent)
    {
        m_object = component;

        connect(m_object, SIGNAL(textColorChanged()), this, SLOT(syncFromQml()));
        connect(m_object, SIGNAL(disabledTextColorChanged()), this, SLOT(syncFromQml()));
        connect(m_object, SIGNAL(highlightColorChanged()), this, SLOT(syncFromQml()));
        connect(m_object, SIGNAL(highlightedTextColorChanged()), this, SLOT(syncFromQml()));
        connect(m_object, SIGNAL(backgroundColorChanged()), this, SLOT(syncFromQml()));
        connect(m_object, SIGNAL(alternateBackgroundColorChanged()), this, SLOT(syncFromQml()));
        connect(m_object, SIGNAL(linkColorChanged()), this, SLOT(syncFromQml()));
        connect(m_object, SIGNAL(visitedLinkColorChanged()), this, SLOT(syncFromQml()));
        connect(m_object, SIGNAL(buttonTextColorChanged()), this, SLOT(syncFromQml()));
        connect(m_object, SIGNAL(buttonBackgroundColorChanged()), this, SLOT(syncFromQml()));
        connect(m_object, SIGNAL(buttonAlternateBackgroundColorChanged()), this, SLOT(syncFromQml()));
        connect(m_object, SIGNAL(buttonHoverColorChanged()), this, SLOT(syncFromQml()));
        connect(m_object, SIGNAL(buttonFocusColorChanged()), this, SLOT(syncFromQml()));
        connect(m_object, SIGNAL(viewTextColorChanged()), this, SLOT(syncFromQml()));
        connect(m_object, SIGNAL(viewBackgroundColorChanged()), this, SLOT(syncFromQml()));
        connect(m_object, SIGNAL(viewAlternateBackgroundColorChanged()), this, SLOT(syncFromQml()));
        connect(m_object, SIGNAL(viewHoverColorChanged()), this, SLOT(syncFromQml()));
        connect(m_object, SIGNAL(viewFocusColorChanged()), this, SLOT(syncFromQml()));
        connect(m_object, SIGNAL(complementaryTextColorChanged()), this, SLOT(syncFromQml()));
        connect(m_object, SIGNAL(complementaryBackgroundColorChanged()), this, SLOT(syncFromQml()));
        connect(m_object, SIGNAL(complementaryAlternateBackgroundColorChanged()), this, SLOT(syncFromQml()));
        connect(m_object, SIGNAL(complementaryHoverColorChanged()), this, SLOT(syncFromQml()));
        connect(m_object, SIGNAL(complementaryFocusColorChanged()), this, SLOT(syncFromQml()));
    }

    void syncToQml(PlatformTheme *object) override
    {
        BasicThemeDefinition::syncToQml(object);

        QMetaObject::invokeMethod(m_object, "__propagateColorSet", Q_ARG(QVariant, QVariant::fromValue(object->parent())), Q_ARG(QVariant, object->colorSet()));
        QMetaObject::invokeMethod(m_object, "__propagateTextColor", Q_ARG(QVariant, QVariant::fromValue(object->parent())), Q_ARG(QVariant, object->textColor()));
        QMetaObject::invokeMethod(m_object, "__propagateBackgroundColor", Q_ARG(QVariant, QVariant::fromValue(object->parent())), Q_ARG(QVariant, object->backgroundColor()));
        QMetaObject::invokeMethod(m_object, "__propagatePrimaryColor", Q_ARG(QVariant, QVariant::fromValue(object->parent())), Q_ARG(QVariant, object->highlightColor()));
        QMetaObject::invokeMethod(m_object, "__propagateAccentColor", Q_ARG(QVariant, QVariant::fromValue(object->parent())), Q_ARG(QVariant, object->highlightColor()));
    }

    Q_SLOT void syncFromQml()
    {
        textColor = m_object->property("textColor").value<QColor>();
        disabledTextColor = m_object->property("disabledTextColor").value<QColor>();
        highlightColor = m_object->property("highlightColor").value<QColor>();
        highlightedTextColor = m_object->property("highlightedTextColor").value<QColor>();
        backgroundColor = m_object->property("backgroundColor").value<QColor>();
        alternateBackgroundColor = m_object->property("alternateBackgroundColor").value<QColor>();
        linkColor = m_object->property("linkColor").value<QColor>();
        visitedLinkColor = m_object->property("visitedLinkColor").value<QColor>();
        buttonTextColor = m_object->property("buttonTextColor").value<QColor>();
        buttonBackgroundColor = m_object->property("buttonBackgroundColor").value<QColor>();
        buttonAlternateBackgroundColor = m_object->property("buttonAlternateBackgroundColor").value<QColor>();
        buttonHoverColor = m_object->property("buttonHoverColor").value<QColor>();
        buttonFocusColor = m_object->property("buttonFocusColor").value<QColor>();
        viewTextColor = m_object->property("viewTextColor").value<QColor>();
        viewBackgroundColor = m_object->property("viewBackgroundColor").value<QColor>();
        viewAlternateBackgroundColor = m_object->property("viewAlternateBackgroundColor").value<QColor>();
        viewHoverColor = m_object->property("viewHoverColor").value<QColor>();
        viewFocusColor = m_object->property("viewFocusColor").value<QColor>();
        complementaryTextColor = m_object->property("complementaryTextColor").value<QColor>();
        complementaryBackgroundColor = m_object->property("complementaryBackgroundColor").value<QColor>();
        complementaryAlternateBackgroundColor = m_object->property("complementaryAlternateBackgroundColor").value<QColor>();
        complementaryHoverColor = m_object->property("complementaryHoverColor").value<QColor>();
        complementaryFocusColor = m_object->property("complementaryFocusColor").value<QColor>();

        Q_EMIT changed();
    }

private:
    QObject *m_object;
};

BasicThemeDefinition::BasicThemeDefinition(QObject *parent)
    : QObject(parent)
{
    defaultFont = qGuiApp->font();

    smallFont = qGuiApp->font();
    smallFont.setPointSize(smallFont.pointSize() - 2);
}

void BasicThemeDefinition::syncToQml(PlatformTheme *object)
{
    auto item = qobject_cast<QQuickItem*>(object->parent());
    if (item) {
        Q_EMIT sync(item);
    }
}

BasicThemeInstance::BasicThemeInstance(QObject *parent)
    : QObject(parent)
{

}

BasicThemeDefinition &BasicThemeInstance::themeDefinition(QQmlEngine *engine)
{
    if (m_themeDefinition) {
        return *m_themeDefinition;
    }

    auto componentUrl = StyleSelector::componentUrl(QStringLiteral("Theme.qml"));
    QFile themeFile{componentUrl.toLocalFile()};
    if (themeFile.open(QIODevice::ReadOnly)) {
        auto data = themeFile.readAll();

        // Before Kirigami 5.80, custom Theme files would be registered as a
        // "Theme" singleton that would then be proxied by BasicTheme. This has
        // changed with the Theme singleton being an instance of BasicTheme.
        // However, this means that old theme files fail to load because
        // QQmlComponent complains about "pragma Singleton". To workaround this,
        // we remove the pragma here, as everything else should still work
        // correctly.
        // TODO KF6: Remove this and rely on all Theme files not being singletons.
        data.replace("\npragma Singleton\n", "");

        QQmlComponent component(engine);
        component.setData(data, componentUrl);
        auto result = component.create();

        if (!result) {
            const auto errors = component.errors();
            for (auto error : errors) {
                qCWarning(KirigamiLog) << error.toString();
            }

            qCWarning(KirigamiLog) << "Invalid Theme file, using default Basic theme.";
            m_themeDefinition.reset(new BasicThemeDefinition);
        } else if (qobject_cast<BasicThemeDefinition*>(result)) {
            m_themeDefinition.reset(qobject_cast<BasicThemeDefinition*>(result));
        } else {
            qCWarning(KirigamiLog) << "Warning: Theme implementations should use Kirigami.BasicThemeDefinition for its root item";
            m_themeDefinition.reset(new CompatibilityThemeDefinition(result));
        }
    } else {
        qCDebug(KirigamiLog) << "No Theme file found, using default Basic theme";
        m_themeDefinition.reset(new BasicThemeDefinition);
    }

    connect(m_themeDefinition.get(), &BasicThemeDefinition::changed, this, &BasicThemeInstance::onDefinitionChanged);

    return *m_themeDefinition;
}

void BasicThemeInstance::onDefinitionChanged()
{
    for (auto watcher : qAsConst(watchers)) {
        watcher->sync();
    }
}

Q_GLOBAL_STATIC(BasicThemeInstance, basicThemeInstance)

BasicTheme::BasicTheme(QObject* parent)
    : PlatformTheme(parent)
{
    basicThemeInstance()->watchers.append(this);

    sync();
}

BasicTheme::~BasicTheme()
{
    basicThemeInstance()->watchers.removeOne(this);
}

void BasicTheme::sync()
{
    auto &definition = basicThemeInstance()->themeDefinition(qmlEngine(parent()));

    switch(colorSet()) {
    case BasicTheme::Button:
        setTextColor(tint(definition.buttonTextColor));
        setBackgroundColor(tint(definition.buttonBackgroundColor));
        setAlternateBackgroundColor(tint(definition.buttonAlternateBackgroundColor));
        setHoverColor(tint(definition.buttonHoverColor));
        setFocusColor(tint(definition.buttonFocusColor));
        break;
    case BasicTheme::View:
        setTextColor(tint(definition.viewTextColor));
        setBackgroundColor(tint(definition.viewBackgroundColor));
        setAlternateBackgroundColor(tint(definition.viewAlternateBackgroundColor));
        setHoverColor(tint(definition.viewHoverColor));
        setFocusColor(tint(definition.viewFocusColor));
        break;
    case BasicTheme::Selection:
        setTextColor(tint(definition.selectionTextColor));
        setBackgroundColor(tint(definition.selectionBackgroundColor));
        setAlternateBackgroundColor(tint(definition.selectionAlternateBackgroundColor));
        setHoverColor(tint(definition.selectionHoverColor));
        setFocusColor(tint(definition.selectionFocusColor));
        break;
    case BasicTheme::Tooltip:
        setTextColor(tint(definition.tooltipTextColor));
        setBackgroundColor(tint(definition.tooltipBackgroundColor));
        setAlternateBackgroundColor(tint(definition.tooltipAlternateBackgroundColor));
        setHoverColor(tint(definition.tooltipHoverColor));
        setFocusColor(tint(definition.tooltipFocusColor));
        break;
    case BasicTheme::Complementary:
        setTextColor(tint(definition.complementaryTextColor));
        setBackgroundColor(tint(definition.complementaryBackgroundColor));
        setAlternateBackgroundColor(tint(definition.complementaryAlternateBackgroundColor));
        setHoverColor(tint(definition.complementaryHoverColor));
        setFocusColor(tint(definition.complementaryFocusColor));
        break;
    case BasicTheme::Window:
    default:
        setTextColor(tint(definition.textColor));
        setBackgroundColor(tint(definition.backgroundColor));
        setAlternateBackgroundColor(tint(definition.alternateBackgroundColor));
        setHoverColor(tint(definition.hoverColor));
        setFocusColor(tint(definition.focusColor));
        break;
    }

    setDisabledTextColor(tint(definition.disabledTextColor));
    setHighlightColor(tint(definition.highlightColor));
    setHighlightedTextColor(tint(definition.highlightedTextColor));
    setActiveTextColor(tint(definition.activeTextColor));
    setActiveBackgroundColor(tint(definition.activeBackgroundColor));
    setLinkColor(tint(definition.linkColor));
    setLinkBackgroundColor(tint(definition.linkBackgroundColor));
    setVisitedLinkColor(tint(definition.visitedLinkColor));
    setVisitedLinkBackgroundColor(tint(definition.visitedLinkBackgroundColor));
    setNegativeTextColor(tint(definition.negativeTextColor));
    setNegativeBackgroundColor(tint(definition.negativeBackgroundColor));
    setNeutralTextColor(tint(definition.neutralTextColor));
    setNeutralBackgroundColor(tint(definition.neutralBackgroundColor));
    setPositiveTextColor(tint(definition.positiveTextColor));
    setPositiveBackgroundColor(tint(definition.positiveBackgroundColor));

    setDefaultFont(definition.defaultFont);
    setSmallFont(definition.smallFont);
}

bool BasicTheme::event(QEvent *event)
{
    if (event->type() == PlatformThemeEvents::DataChangedEvent::type) {
        sync();
    }

    if (event->type() == PlatformThemeEvents::ColorSetChangedEvent::type) {
        sync();
    }

    if (event->type() == PlatformThemeEvents::ColorGroupChangedEvent::type) {
        sync();
    }

    if (event->type() == PlatformThemeEvents::ColorChangedEvent::type) {
        basicThemeInstance()->themeDefinition(qmlEngine(parent())).syncToQml(this);
    }

    if (event->type() == PlatformThemeEvents::FontChangedEvent::type) {
        basicThemeInstance()->themeDefinition(qmlEngine(parent())).syncToQml(this);
    }

    return PlatformTheme::event(event);
}

QColor BasicTheme::tint(const QColor &color)
{
    switch (colorGroup()) {
    case PlatformTheme::Inactive:
        return QColor::fromHsvF(color.hueF(), color.saturationF() * 0.5, color.valueF());
    case PlatformTheme::Disabled:
        return QColor::fromHsvF(color.hueF(), color.saturationF() * 0.5, color.valueF()*0.8);
    default:
        return color;
    }
}

}

#include "basictheme.moc"
